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Traffic woes drive Beijing underground

Bumper-to-bumper traffic has become a dawn-to-dusk nightmare on Beijing's ring roads - but city planners have found an unconventional way around the gridlock.

Matching endless construction above ground, city planners are going subterranean to maximise space in the capital, with plans for extensive underground developments, primarily business centres and parking facilities, cropping up in several districts.

'With the growing economy, Beijing's congestion is also growing at an unprecedented rate,' said independent economist Andy Xie. 'Underground is the only way to go.'

Tongzhou district , on the capital's southeastern outskirts, will hollow out a sophisticated four-floor underground space covering 16 square kilometres, according to Beijing Youth Daily's account of a district people's congress meeting last week.

The first floor below ground is for businesses and subways, the second a network of road tunnels. The fourth floor will be a huge car park with more than 10,000 spaces. Construction of three big tunnels to serve as entrances is scheduled for March.

The newspaper also reported that Dongcheng district , in the east of the city centre, plans to dig under the Temple of Heaven to create a structure with similar functions - parking, transport and business.

Another car park under a high school in Jingshan, the imperial park to the north of the Forbidden City, will cost 300 million yuan (HK$354 million) to create just 300 parking spots.

Chaoyang district , in the east, has started hollowing out space under its central business district. The first floor beneath the ground will feature pedestrian walkways and a so-called business street. The four floors below that will provide 6,000 car parking spaces. A new east-west subway line will connect it to the rest of the city.

Xicheng district, in the inner west, has similar plans for beneath the Temple of the Moon.

A swelling population and a surge in the number of registered vehicles have analysts saying that Beijing has nowhere to go but down.

The city's population has reached around 20 million, and despite caps on car registrations, imposed last month to address the city's round-the-clock traffic congestion, the 4.8 million cars already on Beijing's roads mean it won't be easily fixed.

'The paramount issue is the traffic problem,' Xie said. 'It's just not possible for people to drive.'

Analysts say that building underground is a necessary reaction to overcrowding, with a number of added benefits.

'People like to move from villages to cities, so either we go into the sky or underground,' said Professor Charles Ng Wang-wai, chair in geotechnical engineering at the Hong Kong University of Science and Technology.

Ng is the principal researcher on a 23-professor multidisciplinary team working on a proposal called Green World Underground, which is assessing the costs and benefits of underground urban development.

Ng said that building underground sometimes allowed planners to avoid damaging natural environments and pre-existing structures and avoided certain costs involved with the purchase and acquisition of real estate and work permits. He also explained that although building underground is at least twice as expensive as building above ground, operating a business or car park underground saves on energy and is essentially 'greener'.

'Beijing can benefit from substantial energy saving,' he said. 'Underground, the temperature is fairly constant. Energy consumption would be less, especially given Beijing's weather.'

Ng cited similar large underground developments in Montreal, often described as a 'double-decker city' as a potential solution for Beijing's frost-bitten winters and the associated energy consumption.

'In Montreal, underground developments are mainly for energy conservation purposes,' he said. 'Montreal is very cold. People can walk underground for 26 kilometres without going above ground.'

Beijing's plans have other international precedents. Ng said Europe planned to spend Euro800 billion (HK$8.3 trillion) on underground transport links and infrastructure.

Ng's Green World Underground proposal is meant to assist the Hong Kong government in its own endeavours to use underground space, under an initiative launched last year.

There are, however, considerable costs and safety concerns about turning Beijing into a double-decker city, and not everyone's convinced it's worth it. Professor Liu Qifei, a delegate to Beijing's municipal Chinese People's Political Consultative Conference, criticised the plan as ruthless and illegal in a recent Xinhua article.

'Underground space is public space that needs to be developed scientifically and carefully,' Liu said. 'Shame on us if a rush results in some permanent damage that future generations can't repair.'

Citing a host of potential construction problems, Hong Kong tunnelling expert Dr Ian McFeat-Smith said that the integrity of existing buildings could be endangered. 'There will be impact from blast vibrations,' he said. 'You can have cracking in the surrounding buildings.'

McFeat-Smith, who has 33 years' experience in underground construction in Hong Kong, said Beijing could avoid problems posed by traditional methods of underground tunnelling like blasting by using mechanised tunnelling, but there were still many potential pitfalls.

'If you also intercept a water head or fault zone unexpectedly, it could cause catastrophic collapse into the excavation - as they did in Shanghai when building the Shanghai metro,' he said.

Underground development could put at risk the integrity of buildings in Beijing's central business district as well as cultural heritage sites like the Temple of Heaven. Yet-to-be excavated historical artefacts were also a concern, he added.

Ma Guoxin, chief architect and senior engineer at the Beijing Institute of Architectural Design, said: 'Beijing is a very old city - 3,000-plus years. Underground, there are going to be cultural artefacts, and that's a very important thing to consider.'

Public safety is also a paramount issue. Last year, a study by the Beijing Geotechnical Institute concluded that big underground structures in Beijing would be prone to flooding.

After analysing hundreds of years of Beijing's historical records, meteorological data on extreme weather, imbalanced underground water distribution and unique rock structure, researchers led by Dr Wang Junhui found that a single summer storm could submerge the city's whole underground ambition.

Beijing does not have an effective drainage system to collect rain water. After rain, the first place that surface water would go and stay is man-made holes.

And water isn't the only problem. McFeat-Smith said adequate ventilation of the underground space should be a major concern, because 'methane could come in during construction from strata or during operation from cars, and if it reaches a critical level it can cause an explosion'.

Despite the major risks, he still thinks the projects should not be entirely discounted.

'Risk is the frequency of a hazard multiplied by the consequence,' he said. 'It's very good to think about going underground, but Beijing has to think of the geotechnical hazards.'

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